Help me get my KZ400 running...Carb jet advice.

Hello all,

This is my first post. I recently came into possession of a 1978 KZ400-B1 with only 4000 original miles on it and it hasnt been started in 15 years or more. It would appear that mechanically it is fairly sound, but cosmetically it has a lot of surface corrosion/tarnish on the chrome/metal bits.

Anyway, I am starting the process (slowly as I do not have a lot of free time) of trying to get the bike to turn over an run before I go about making any cosmetic repairs/modification.

I have 5 sets of carbs for the bike that were given to me (the originals plus 2 more 78 sets, a 77, and a 79...all of them have various damage/rot, tarnish...but between them all I can make a good set or two of carbs).

I have purchased two Keyster carb rebuild kits for the 78 B1 carbs ($15 each) and a Uni Filter ($25) and the bike already had black Mac Trumpet style exhaust. And it is likely I will replace the coil with an aftermarket unit for a little better spark. With that said, I would like to go up 2-3 jet sizes for the air filter and exhaust while I am doing the rebuild but have no idea where to find jets for this carb (is it a VB32 or 32x2) or what size drill bit I would need if I attempt to drill out the jets. Should I shim the needle? Any advice?

If the bike gets running I may keep it stock or go cafe racer style in the future as I need to sell my 2011 Vstar cause I have a child on the way and want to keep the bike that doesn't require payments! THANKS.

Is that Uni filter made to go inside the airbox?

If you are not using the airbox, jetting will be quite a long process to get right. Make sure the diaphragms on the carbs are in tact and in very good shape. Any cracks will soon be leaks and will make jetting near impossible.

Welcome aboard. I'd bet that either Z1E or Sudco have the jets you need.

Uni filer goes inside airbox....and the diaphragms are in good shape...even bought a set of replacements.

The jets are really my main issue before going forward

thanks

Still curious as to what size jets to get for pilot and main and if air jet needs to be changed also. Anyone with an answer please let me know.

There's football on so be patient...
Get the bike running and then worry about jets and clips. If you are using the airbox and you have a street baffle in your pipe, your stock jets will be close but you need to know the bike is running correctly to know what to do next.

mykenytemare wrote: Still curious as to what size jets to get for pilot and main and if air jet needs to be changed also. Anyone with an answer please let me know.

Would keep existing jets until after assuring valve clearances are within specs, positive compression test results, ignition timing set spot on, visually observing fat blue sparks on both plugs, confirming correct fuel level via clear tube tests, assuring ample clean fuel supply to carbs, proper functioning of petcock, absence of crud or grit inside fuel tank (flush if necessary), install new aftermarket in-line fuel filter, thoroughly clean all carb circuits, and set pilot adjuster screws for best idle performance.

Then it would be time to address the possible desirability for any changes to the existing jetting. Which might have already been changed when the Mac exhaust system was installed. Would compare existing jet size to oem sizes.

Even perfect carbs can't compensate for deficiencies in the other areas.

Good Fortune!